The present invention relates to the reduction of cholesterol levels in the blood supply of warm blooded animals, and particularly in humans.
The condition known as atherosclerosis has long been recognized as a major contributor to death due to cardiovascular failure. Particularly, it is determined that certain deposits of fatty tissue, known as lipids develop on the internal walls of arteries, and cause constrictions which drastically reduce blood flow and place greater strain on the heart. Also, these fatty deposits frequently dislodge and form emboli that can lodge in other vessels and result in their total blockage. Though a variety of causes have been outlined and are under study, the development of the condition, known as hyperlipidemia, wherein such fatty deposits form, has been studied and determined to be directly related to excessively high levels of the compound cholesterol in the blood stream. Specifically, increased risk for premature ischemic heart disease in young men has been found when the cholesterol concentration exceeds two hundred and twenty (220) milligrams per one hundred (100) milliliters of blood plasma.
A variety of treatments have been developed in recent years and proposed for reducing the cholesterol level in the blood. Specifically, one of the approaches has been to sequester or complex bile acids and remove them from the system. It has been found that when the bile acids are so removed from the enterohepatic circulation, there is an increased hepatic conversion of cholesterol to bile acids. Thus, in instances where bile acid levels were reduced, cholesterol levels dropped. Specifically, cholestyramine, a resinous bile acid sequestrant comprising a copolymer of styrene and divinyl benzene and containing trimethyl benzyl ammonium groups, was administered in amounts of 12 to 28 grams to human test patients, and cholesterol levels dropped 25%.
Though cholestyramine and other resins have been prepared and have been orally administered, their use has not been widely accepted. Specifically, the resins possess an unpleasant sandy texture and must be ingested in large amounts. Additionally, the administration of these resins has been observed to cause nausea and constipation, and the resins have been found to lack the chemical specificity that is necessary to interact exclusively with bile acids; thus, frequently drugs, food materials and other anionic materials in the body will interact with the resin and will reduce the efficiency of its bile acid removal.